1. Field of the Invention
The present invention relates generally to the sealing off of well bores in wells such as geothermal, water or oil wells where it is necessary to provide a stronger lining than can be obtained with rigid foam alone without pumping concrete or similar materials into the well. If there is difficulty in cementing off due to saltwater or an underground stream, a foam forming mixture reacts and hardens in minutes whereas concrete takes a longer time and may wash away in the process.
2. Description of the Prior Art
Many methods and devices for plugging and lining well bores under different circumstances and for different purposes have proposed to solve this problem. Examples include this inventor's U.S. Pat. No. 3,726,340 dated Apr. 10, 1973 and this inventor's co-pending U.S. patent application Ser. No. 127,585 filed Mar. 6, 1980, and now U.S. Pat. No. 4,276,934. This is another solution to the problem and provides a high-strength, rigid lining without the necessity of, and the complexity and delay associated with pumping concrete into a well and waiting for it to harden and cure. The present invention discloses a device and method for lining the well bore hole with a reinforced polyurethane or other type of foam which is generated in place.